Date Available

7-28-2015

Year of Publication

2015

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Education

Department/School/Program

Kinesiology and Health Promotion

First Advisor

Dr. Mark Abel

Abstract

This dissertation is composed of two manuscripts assessing cardiovascular disease (CVD) risk in structural firefighters. Study 1 compared traditional CVD risk factors and health-related behaviors between professional and volunteer firefighters. Online questionnaires were sent to approximately 4000 firefighters in the state of Kentucky. The results indicated that 90% of volunteer and 58% of professional firefighters were classified as moderate-to-high CVD risk. Volunteer firefighters were significantly (p < 0.001) older and more likely (p = 0.026) to be current cigarette smokers. The mean body mass index among all firefighters in the sample was 30.8 kg·m-2. Nearly 60% of volunteer firefighters were obese. Obese firefighters were more likely (p < 0.05) to have been diagnosed as diabetic or pre-diabetes compared to overweight and normal weight firefighters. These results indicate that volunteer firefighters may be at a greater CVD risk compared to professional firefighters.

Study 2 investigated the association of cardiorespiratory fitness (CRF) and body fat with arterial stiffness in professional firefighters. Forty-six male professional structural firefighters performed a maximal graded exercise test in personal protective equipment and noninvasive arterial stiffness assessments before and for 60 minutes post-exercise. Percent body fat was measured with a bioelectrical impedance analyzer. Firefighters were stratified into fit (VO2peak ≥ 48.3 ml·kg-1·min-1) and unfit (VO2peak < 48.3 ml·kg-1·min-1) groups. Pulse wave velocity, an indicator of arterial stiffness, was significantly lower overall in the fit group compared to the unfit group (p < 0.001). However, the fit group had significantly less relative body fat compared to the unfit group. Thus, when controlling for the confounding effects of fatness, the results indicated that there was a significant effect of relative body fat (p < 0.001) but no effect of fitness on arterial stiffness (p = 0.490). This indicated that relative body fat was responsible for the difference in arterial stiffness and not the fitness stratification. The unfit group displayed a significantly higher average carotid-femoral pulse wave velocity of 1.004 m·s-1 which may increase the risk of a sudden cardiac event by 14%. In addition, there was no main effect for time (p = 0.794) or group x time interaction (p = 0.906). Most resting measures of central and brachial pressure were significantly higher in the unfit group.

Results from this dissertation indicated that volunteer firefighters have a greater CVD risk than professional firefighters. Furthermore, relative body fat has a greater effect on arterial stiffness than cardiorespiratory fitness. Collectively, these findings indicate the need for innovative weight management strategies to decrease CVD risk among structural firefighters.

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